class Mongo::ServerSelector::SecondaryPreferred

Encapsulates specifications for selecting servers, with

secondaries preferred, given a list of candidates.

@since 2.0.0

Constants

SERVER_FORMATTED_NAME

Name of the this read preference in the server's format.

@since 2.5.0

Public Instance Methods

name() click to toggle source

Get the name of the server mode type.

@example Get the name of the server mode for this preference.

preference.name

@return [ Symbol ] :secondary_preferred

@since 2.0.0

# File lib/mongo/server_selector/secondary_preferred.rb, line 39
def name
  :secondary_preferred
end
slave_ok?() click to toggle source

Whether the slaveOk bit should be set on wire protocol messages.

I.e. whether the operation can be performed on a secondary server.

@return [ true ] true

@since 2.0.0

# File lib/mongo/server_selector/secondary_preferred.rb, line 49
def slave_ok?
  true
end
tags_allowed?() click to toggle source

Whether tag sets are allowed to be defined for this server preference.

@return [ true ] true

@since 2.0.0

# File lib/mongo/server_selector/secondary_preferred.rb, line 58
def tags_allowed?
  true
end
to_doc() click to toggle source

Convert this server preference definition into a format appropriate

for a server.

@example Convert this server preference definition into a format

for a server.
preference = Mongo::ServerSelector::SecondaryPreferred.new
preference.to_doc

@return [ Hash ] The server preference formatted for a server.

@since 2.5.0

# File lib/mongo/server_selector/secondary_preferred.rb, line 91
def to_doc
  @doc ||= (preference = { mode: SERVER_FORMATTED_NAME }
    preference.merge!({ tags: tag_sets }) unless tag_sets.empty?
    preference.merge!({ maxStalenessSeconds: max_staleness }) if max_staleness
    preference)
end
to_mongos() click to toggle source

Convert this server preference definition into a format appropriate

for a mongos server.

Note that the server preference is not sent to mongos as part of the query

selector if there are no tag sets, for maximum backwards compatibility.

@example Convert this server preference definition into a format

for mongos.
preference = Mongo::ServerSelector::SecondaryPreferred.new
preference.to_mongos

@return [ Hash ] The server preference formatted for a mongos server.

@since 2.0.0

# File lib/mongo/server_selector/secondary_preferred.rb, line 75
def to_mongos
  return nil if tag_sets.empty? && max_staleness.nil?
  to_doc
end

Private Instance Methods

max_staleness_allowed?() click to toggle source
# File lib/mongo/server_selector/secondary_preferred.rb, line 116
def max_staleness_allowed?
  true
end
select(candidates) click to toggle source

Select servers taking into account any defined tag sets and

local threshold, with secondaries.

@example Select servers given a list of candidates,

with secondaries preferred.
preference = Mongo::ServerSelector::SecondaryPreferred.new
preference.select([candidate_1, candidate_2])

@return [ Array ] A list of servers matching tag sets and acceptable

latency with secondaries preferred.

@since 2.0.0

# File lib/mongo/server_selector/secondary_preferred.rb, line 112
def select(candidates)
  near_servers(secondaries(candidates)) + primary(candidates)
end